Process for the manufacture of custom optical elements

ABSTRACT

A process for the manufacture of custom freeform optical elements utilising parameterised modelling. A system for the automatic manufacture of a custom optical element is also described with the manufacturing being by laser micro-machining. The process and system allow customers to specify and order via a web interface and so reduce engineering time, overhead and cost.

The present invention relates to manufacturing optical elements and moreparticularly to the manufacture of custom freeform optical elements.More specifically, the present invention relates no an improved methodfor optical element manufacture utilising parameterised modelling toallow customers to specify and order via a web interface and so reduceengineering time, overhead and cost.

In constructing an optical system such as a high power diode laseroptical elements are required to manipulate the beams and provide adesired output. While some conventional optics, these being plane optics(prisms, windows, flats and wedges), lenses (spherical, aspherical,cylindrical and acylindrical forms) and mirrors exist as catalogue itemsit is more typical that the customer will supply drawings andspecifications to the vendor. Subsequently a price is agreed and thevendor manufactures the optical element to the customer's specification.

With the increase in laser specifications and application areas, moreadvanced optical components are being designed. For example,US2012/140334 to the present Applicant's describes a freeformmicro-optical element being a fast axis collimator array for use with ahigh power diode laser having diode bars of emitters which are arrangedin stacks providing a two-dimensional array of emitters. The diode barsare typically fabricated with 25 emitters of 200 μm width along a 10 mmbar of semiconductor, on typically 1.8 mm pitch. To usefully use theoutput, each beam from each emitter requires to be collimated. Themicro-optical element for use with this laser diode bar stack, providesan element comprising a plurality of fast-axis collimators to match theplurality of emitters, formed as a monolithic two-dimensional array. Inthis way, the array dimensions are matched to the number of emitters anda manufacturer needs only to mount a single optical element at the endof the laser diode bars, consequently reducing the potential formisalignment while increasing the speed of construction. As thedimensions of the element are approximately 1 cm², the element is alsoeasier to handle than multiple discrete lenses which are used in theprior art at each emitter of bar.

The advancements in laser micro-machining have now made such freeformmicro-optical elements accessible as a micro-optical element is producedwhich avoids the tooling or mask writing steps of alternative techniquesand provides for faster fabrication. A laser micro-machining techniqueis described in US 2012/0140334 and US 2012/0298650 to the presentApplicant's. In this method of manufacturing a micro-optical element, alaser is translated over a fused silica substrate to ablate portions ofthe substrate in a shot-by-shot raster regime. Thus lens shapes can becreated on the surface of the substrate. Further, by melting the surfaceof the silica in zones greater than the raster pitch, the residualpattern of the raster is removed and a smooth, polished surface isachieved. This step can also be achieved rapidly and provides a higherstandard of smoothing than the mechanical polishing techniques used inconventional optical fabrication.

While the Applicant's can manufacture to their own specificationseasily, the process becomes more difficult when a customer wishes theApplicant's, as vendors, to fabricate a new freeform optical design.Currently, a specification of the customer optic requirement is obtainedand then assessed to see whether their requirement is achievable withthe current manufacturing process. The vendor may need to carry outadditional optical design and analysis as required to see if therequired design is achievable. For example, the customer may specify anumber of lens shapes over a total width of the element. Calculationsmust then be done to determine if the resulting pitch will result introughs between lens shapes being smaller than the resolution obtainablein laser micro-machining.

If the customer optic requirement is not achievable with existingprocesses, the vendor must assess whether a design cycle would enable anew process to allow manufacture of the optic required. The vendor alsoneeds to establish test requirements for confirming acceptableperformance of the finished optic. At this stage the vendor interfaceswith the customer to allow them to either provide: design data in aformat suitable to enable manufacture of the optic; data specifyingoptical functionality sufficient to enable design of the optic; or,measurement data sufficient to enable design of the optic.

The vendor can then undertake the redesign and communicate this back tothe customer. This may be an iterative process to ensure that thecustomer gets an optic which will be fit for purpose and the vendor canmanufacture the optical element using the laser micro-machining process.It is not unusual for the vendor to have to visit the customer's siteand make further measurements on the customers system, such asdetermining the trajectory of each beam from an array of emitters in ahigh power laser diode stack as the emitters are not uniformly aligned.

The vendor then designs the optic and the design must be reviewed todetermine whether it can be fabricated in accordance with the requiredspecification, communicating with the customer as required.

The next stage is for the vendor to fabricate a trial optic and measureits form error (the deviation in measured surface form from designedsurface form) to ensure the part will meet the agreed uponspecification. If the optic does not meet the specification, the vendorneeds to define a set of adjustments to the fabrication instructions inorder to reduce the form error. They then repeat the cycle offabrication, test, and adjust until the optic meets the specification.

Once the specification is met, which has to be confirmed by undertakingthe tests formulated earlier, the vendor then fabricates the number ofproduction optics required by the customer. The parts are then AR coatedand diced into a custom shape, if required. Following inspection andyield of the final parts, they can be packaged and delivered to thecustomer.

The major disadvantage in this approach is that because varying levelsof engineering work are required between jobs, the final price per opticis not standardised; meaning that human input is typically required toprice a job and indeed, the job cannot be priced until an amount of manhours has already been committed.

The main disadvantage to the vendor is that they must expend significantengineering time and production overhead both to define the parts and toenable manufacture of the parts within specification. There is asignificant overhead in communication with the customer from initialinquiry to delivery of parts. The level of development resource requiredmay be unclear at the outset, adding to cost and commercial risk.

The main disadvantage to the customer is that they must expendsignificant engineering time in communicating their requirements withthe vendor. The level of engineering resource required to do this may beunclear at the outset, leading to reluctance on the part of the customerto commit resource to an uncertain outcome. Also, as pricing depends onthe level of engineering effort expended by the vendor, the customermust expend considerable effort before knowing whether the part can bemanufactured, and whether the job will have an acceptable price.

Consequently, specification and manufacture of freeform opticalcomponents typically requires significantly higher engineering inputthan for conventional optics, the vendors of freeform optical componentstypically charge correspondingly high levels of NRE, often making themanufacture of prototype parts prohibitively expensive.

It is therefore an object of the present invention to provide a processfor the manufacture of custom optical elements which mitigates at leastsome of the disadvantages of the prior art.

According to a first aspect of the present invention there is provided aprocess for the manufacture of a custom optical element, the processcomprising the steps:

-   -   a) providing a set of optical design guidelines and file format        over a web-interface;    -   b) inputting an optical design in the file format via the        web-interface;    -   c) applying a checking routine to determine if the optical        design meets the guidelines and manufacturing limitations;    -   d) altering the design to the extent required to provide a        conforming design which meets the guidelines and the        manufacturing limitations;    -   e) displaying the conforming design over the web-interface;    -   f) ordering at least one optical element in the conforming        design; and    -   g) manufacturing the optical element(s) in the conforming        design.

In this way, an automatic process is provided which offers a choice froma variation of adjustments to an optical design in order to turn adesign that does not comply with design guidelines into a part thatsatisfies these design guidelines.

The cost to the vendor is reduced by removing the need for engineeringinput into the design and fabrication process, the cost of manufactureis both reduced and made predictable. This allows the vendor to offercomplex, freeform optics for a low and fixed price. Lead time is reducedand made predictable for similar reasons.

The cost to the customer is also reduced provided the customer has thedesign capability to specify the optic according to the guidelines, thecustomer's internal costs are reduced as they do not need to engage intime consuming communication with the vendor, the overheaded cost ofwhich can easily exceed the purchase order value for prototype parts.Also, certainty of price and lead time make the customer far more likelyto place an order.

The vendor can take orders from new customers with greatly reduced costof sales, which allows for the vendor to expand its market share toinclude customers that previously were unobtainable.

Additionally, the manufacturing limitations can be hidden from thecustomer so that they do not need to have access to proprietary andconfidential information regarding the manufacturing process.

Preferably, step (d) includes providing a plurality of conformingdesigns. In this way a customer can choose from a set of proposeddesigns, so that if the first conforming design does not meet theirrequirements, they do not have to design and input a new optical design.

Preferably, the optical design is displayed over the web-interface. Inthis way, a customer can see that they have input the design in thecorrect file format.

Preferably, a specification to which a conforming design will be testedand/or inspected is provided in step (a). In this way, the customer canbe assured that a manufactured optical element will meet theirrequirements.

Preferably, the file format is one which involves sampling an opticalsurface, according to the optical design, with a grid in order todescribe the optical surface to an external computer program withsufficient resolution. In this way, the formatted file can foe sentdirectly to and used directly in the manufacturing process. In anembodiment the manufacturing process is laser micro-machining. In thisway, the formatted file may contain a grid of data which valuesrepresent the depth of ablation of the surface of a substrate to providethe optical design.

Preferably the process includes a step of making payment for the opticalelements via the web-interface. In this way, the process can be used asan on-line ordering and payment system.

Preferably, steps (c) and (d) are automated, by the provision ofcomputer programs which operate on the input optical design file.Alternatively, steps (c) and (d) may be performed by an engineer, whichwill still reduce the process time as their will be no requirement forcustomer interaction.

Preferably also, the process includes the steps of adding optionalspecifications to the optical design. For example, the choice of havingan anti-reflective coating applied to the optical element can be givenwith the coating being applied during manufacture.

According to a second aspect of the present invention there is provideda system for the automatic manufacture of a custom optical elementcomprising: a first module including a web-interface, data storagemeans, data processing means and data display means; an input opticaldesign being a file containing data referenced to a grid which describesa surface in three dimensions; and an optical element manufacturingprocess; wherein a set of optical design guidelines and a set ofmanufacturing limitations are stored in the data storage means andaccessed by the data processor to check against the input optical designand generate one or more alternative optical designs which meet theguidelines and limitations if the input optical design does not, eachoptical design being displayed by the display means over theweb-interface and a selected optical design being transferred as aninput file to control the manufacturing process and produce at least oneoptical element to the selected optical design.

In this way, an automatic system is provided which offers a choice froma variation of adjustments to an optical design in order to turn adesign that does not comply with design guidelines into a part thatsatisfies these design guidelines and then to manufacture said design asan optical element.

Preferably, the manufacturing process is a laser micro-machiningfacility. More preferably, the laser micro-machining facility melts andablates a fused silica substrate to create the optical element.

An embodiment of the present invention will now be described, by wayonly, with reference to the accompanying drawings, of which:

FIG. 1 is a flow chart illustrating steps in a process for themanufacture of a custom optical element, according to an embodiment ofthe present invention;

FIG. 2 is an illustration of an optical element to an input opticaldesign according to an embodiment of the present invention;

FIGS. 3(a) and (b) are illustrations of the optical element of FIG. 2with customised optical designs according to an embodiment of thepresent invention; and

FIG. 4 is a schematic illustration of components and steps inmanufacturing a micro-optical element using laser micro-machiningaccording to an embodiment of the present invention.

In order to assist in the description of the invention, we shallconsider an optical element for the process. This is by way of exampleonly and should not be considered to limit the scope of the invention inany way.

Referring initially to FIG. 1 of the drawings, there is illustrated aprocess, generally indicated by reference numeral 10, for themanufacture of a custom optical element according to an embodiment ofthe present invention.

The first step in the process is the customer optical design submission.Here the customer's engineers define an optical design to meet theirsystem requirements. In this example, the customer's system is a highpower diode laser. High power diode lasers are used in applications suchas pumping of solid state lasers and directly in materials processing.In order to achieve the required power levels, diode bars of emittersare arranged in stacks providing a two-dimensional array of emitters.The diode bars are typically fabricated with 25 emitters of 200 μm widthalong a 10 mm bar of semiconductor, which is then solder-bonded to amicro-channel watercooled heat sink. Commercially produced units,emitting 50-100 W per bar, are stacked on typically 1.8 mm pitch tobuild up a total laser power of 500-1000 W. For our customer, theirarrangement has four diode bars, having five emitters along each bar.

While such an arrangement produces high power, the beam quality isunacceptable. For high-brightness applications and also for somemedium-brightness applications, by which we mean those with divergencewell below the ex-facet divergence but well above the diffraction limit,the beam must be, at least, collimated. Manufacturers typically attachan individual fast-axis collimator to each bar. The fast-axis collimatoris a plano-cylindrical lens which is used to provide low aberrationcollimation for the high numerical aperture fast-axis beam. Thefast-axis refers to the vertical axis where the beam diverges quicklyfrom art emitter region in the μm range. This is in contrast to theslow-axis, parallel to the face of the bars, where the emitter region ismore typically 100 μm.

For many applications, the resultant beam quality is still poor. Thedisadvantages in using a plano-cylindrical lens at along each bar areapparent as: the cylindrical lens for each bar introduces angularaberrations giving a local radiance loss of a factor of 2 to 3; thecollimation lens cannot be correctly positioned for all points along thebar as a result of the “smile” effect, where the semiconductor bar isbent by differential expansion during solder bonding, resulting in beamswith variable pointing direction; and errors in attaching the fast-axiscollimator to the heat sink with the required positional accuracy alsodegrade the angular spectrum of the emitted light. Additionally, in manyapplications of the laser diode stacks, subsequent aperture filling,beam shaping and beam combining optics are required and, due to errorsin ray angles from the fast-axis collimator, the design andeffectiveness of subsequent beam conditioning optics is compromised.

Due to the difficulty in positioning discrete collimators at eachemitter and the inability of a plano-acylindrical lens positioned alongeach bar to correct for smile and facet bending, US 2012/0140334 to thepresent Applicant's discloses a micro-optical element for use with anedge-emitting laser diode bar stack which is of single piececonstruction. The element comprises a plurality of spaced apartfast-axis collimators formed as a monolithic array, wherein the spacingbetween the collimators in the fast-axis varies across the micro-opticelement. Such a monolithic array provides a surface of lenses withproperties tailored to the geometry of the laser diode stack. US2012/0140334 is incorporated herein by reference. This monolithic fastaxis collimator array is what the customer desires.

The customer's engineers will consult documentation available on thevendor's website that describes the product, the design guidelines andfile format, and the specification to which the part will be inspected.Using these guidelines, the customer's engineers define an opticaldesign to meet their system requirements. This design can be donemathematically or numerically using programs such as MATLAB orMathematical, with optical design packages such as ZEMAX or CODE V, orwith simpler tools such as a spread sheet. The customer then saves theiroptical design into a portable file format defined by the vendor. Thisinvolves sampling the optical surface with a specific grid in order todescribe the surface to an external program with appropriate resolution.

Via the web-interface 14, the customer then uploads the design file tothe website in order to submit it for manufacture. A part visualisationstep 16 may be made here, where the customer is presented with an imageshowing what the optical element 50, made to their design, would looklike. This three-dimensional representation is shown in FIG. 2.

FIG. 2 illustrates an optical element 50 being a monolithic fast axiscollimator array. The customer's engineers have designed twentyplano-cylinder lenses 52 on a surface 54. Each lens 52 is designed tocollimate the beam from each of the twenty five emitters on their highpower diode laser. Each lens 52 is orientated to intercept and correctthe trajectory of the beam from each emitter, so that a parallel arrayof collimated beams will exit the element 50, in use. The visualisation16 can be used by the engineers to confirm that they have correctlyinput the data in the correct file format.

The vendor's then has a stored model of a fast axis collimator array andcompares this to the input design 50. An initial check is performed tosee that it meets the guidelines, which in this case may be that atwo-dimensional array of plano-cylindrical lenses will represent amonolithic fast axis collimator array. An on-line rule check formanufacturability 18 is then performed. In this step, the vendor canhold data on the manufacturing limitations and techniques used, whichare not accessible to the customer. In this way, the vendor does notreveal proprietary or confidential information about the manufacturingprocess which may, if published, allow others to offer the manufacturingprocess.

For this example and as an embodiment of the present invention, themanufacturing process is a laser micro-machining technique. The lasermicro-machining technique is described in US 2012/0140334 and US2012/0298650 to the present Applicant's, which are incorporated hereinby reference.

Reference is now made to FIG. 4 of the drawings which illustrates thecomponents of a laser micro-machining process, generally indicated byreference numeral 30, for creating a micro-optical element 50 for usewith a laser diode bar stack. An RF excited CO₂ laser 32 is arrangedbefore an acousto-optic modulator (AOM) 34. Various optical elementsdirect the output beam 36 to a silica substrate 38 upon which the lensshapes 52 will be machined.

The fused silica substrate 38 (typically a piece of flat, parallel-sidedfused silica 1 mm thick) is mounted upon an XY translation stage 40,which is computer 42 controlled to move in steps of 100 nm in the twodimensions. A focussing lens 44 mounted on a computer controlled Z stage46, focuses the beam 36 onto the substrate, a required depth to ablatethe silica. The computer 42 moves the stages 40,46 in a rasterconfiguration so that controlled ablation, by shot-by-shot laserwriting, of the silica 38 is achieved to create the required lens shapes52 to form the array of fast-axis collimators.

In order to achieve laser pulses of equal energy, high stability andfixed on a single laser line, a process of timed signals, is followed.The stage 40 controller 42 generates a position-synchronised output(PSO) trigger when the stage 40 passes predefined locations. This is astandard feature on many commercial XY stages and controllers. Thesetrigger signals are used to fire the laser 32. Advantageously, the AOM34 window opens at time which ensures that the spectrum has settled inthe delivered pulse. Pulse energy is kept constant by feedback controlvia a detector signal from a partially reflected beam being fed to apulse energy dispenser for a pulse energy target.

Typically the spot on the substrate 38 corresponds to a Gaussian beamwaist such that the spot profile at the surface to be machined iscircular Gaussian. The beam radius may be on the order of approximately25 μm.

The time needed to machine each lens shape 52 is approximately 10minutes. The entire element 50 can thus be manufactured in a relativeshort amount of time providing the ability to undertake rapidprototyping.

The as-machined surface 52 of the element 10 is then subjected to arectangular mesh of shots. The mesh is selected as 2 μm by 10 μm and thelaser selected to give fluencies of approximately 5 to 8 J/cm². A meltzone of diameter approximately 220 μm is thus created which removes theresidual pattern of the raster and smoothes the surface 52. It is thesame system, as described with reference to FIG. 4, which performs thesmoothing and thus the substrate 38 does not require to be moved betweenthe machining and polishing steps.

An on-line rule check for manufacturability 18 checks the optical design50 for compatibility with the manufacturing process. It then eitherconfirms that the optical design can be directly manufactured tospecification, or gives feedback that it cannot. In the present example,we can consider that the check found that the troughs 60 between thelens forms 52, where too narrow and not achievable by the lasermachining process. Additionally, the thickness of substrate left betweenthe base 58 of the troughs 60 and the back surface 58 would produce anelement which would be too fragile. Thus the on-line check formanufacturability 18 fails.

The system then provides routines to generate a selection of solutionsfor the failed rules or conditions 20. In the present example, twoalternative designs are proposed. These are illustrated in FIGS. 3(a)and 3(b). In the element 50 a, the troughs 60 a have been widened andmade shallower. This increases the thickness between the base 58 a andthe back surface 56 a. The lens forms 52 have been combined to form asingle plano-cylindrical lens 54 for each laser bar. This has been doneas the radius of curvature of the largest lens 52 has been used to fitover the emitters. In this design the correction of emitter misalignmenthas been traded against the numerical aperture for each beam. The secondalternative design, element 50 b, has maintained the individualplano-cylindrical lenses, but at reduced dimensions to provide thewidened trough 60 b. In the element 50 b, the troughs 60 b have alsobeen made shallower. This increases the thickness between the base 58 band the back surface 56 b. The two alternative design solutions 50 a, 50b are checked again 18 to confirm that the new surfaces conform to theguidelines and the manufacturability criteria.

The alternative designs 50 a,b are generated visually and together withdata on their specification and performance are presented to thecustomer 20 over the web-interface. The customer is given the option ofchoosing one of the design alternatives 22 once they have checked thatone of these will suit their requirements. Alternatively they can changethe design and resubmit. Once the customer has chosen the design, otheroptions can be offered such as an AR coating.

With the design selected (in this case 50 b), the customer can order therequired number of optical elements 50 b through the website and payeither by credit card with a standard e-commerce interface or byapplying/paying through an account with the vendor.

In an automated process, the original or modified design 50 b files aresent to the laser micro-machining system 30, where they are used toprogram the fabrication process for the number of optical elementsordered 24. As the system is computerised, the customer can have accessto the production status 26 at any time. On completion, the fused silicaoptical element will have a surface matching that of the original design50 b. The elements 50 b may be AR coated if the option has beenselected. The final parts are then inspected and tested to ensure theymeet the test protocol presented at the start of the process 12. Theoptical element(s) is then delivered to the customer 28.

Thus, the process 10 of the present invention significantly simplifiesthe process of obtaining a new customer, as well as simplifying theprocess for existing customers to obtain new bespoke optical parts. Byoffering a standardised specification, manufacturing process, productlayout and data exchange format, the vendor is able to eliminate many ofthe steps required by the existing prior art process. The process isexecuted primarily through a website interface and aims to minimise theamount of time spent interacting with the customer.

The principle advantage of the present invention is that it provides aprocess and system for the manufacture of custom freeform opticalelements where the file the customer submits is the file directly usedby the laser fabrication system in order to produce the optical element;but the level of standardisation in the process means the customer doesnot require any knowledge of how the laser fabrication process works. Inessence this means the customer is able to exactly specify the surfacethey desire and the vendor's process manufactures that surface (withinspecification and assuming guidelines have been adhered to) with a highlevel of automation (i.e. without the need for anyone at the vendors toexercise human judgement over the specific design or the process used),minimising engineering time and eliminating any iterative fabrication,test, and adjust cycles. Humans may still be used for standard handlingand inspection steps, but these are standard across all products and arenot product-specific.

A further advantage of the present invention is that it provides aprocess and system for the manufacture of custom freeform opticalelements which automatically checks whether the design fits within thisprocess capability and where it does not, automatically offersvariations to the design that do fit within this process capability.Consequently, the customer can rapidly arrive at a design that they knowwill be made to specification and choose between alternatives that bestsuit their requirements.

It will be appreciated by those skilled in the art that variousmodifications may be made to the invention herein described withoutdeparting from the scope thereof. For example, the guidelines maysuggest typical optical elements for the customer to input theirrequirements. Though the process assumes that the customers havesignificant optical design expertise, the process could include links tooptical design packages for those of less skill in the art.Additionally, the process could include ray optic illustrations of theexpected performance of the optical element to further assist a customerin making sure that the design selected best meets their requirements.Further also, the process may offer other processes such as amending thedesign to correct for wavefront error that needs correction. Theseadd-ons may require further data from the customer and engineering inputfrom the vendor, but by interacting over a web-interface the steps areautomated, clear and reduce the amount of customer interaction time.

We claim:
 1. A process for the manufacture of a custom freeform opticalelement, comprising the steps of: a) creating a set of optical elementdesign guidelines and a file format for a custom freeform opticalelement, storing said guidelines and said file format on a processor,and providing said guidelines and said file format over a web-interfaceto a customer; b) inputting said customer's desired optical elementdesign and transmitting said customer's inputted desired optical elementdesign in the file format, via the web-interface, from said customer toa vendor; c) applying, by a computer of said vendor, a computerizedchecking routine to compare said desired optical element design withsaid optical element design guidelines to determine if said desiredoptical element design meets said optical design guidelines and anapplicable set of manufacturing limitations; d) employing, by aprocessor, parameterised modelling to alter the desired optical elementdesign to the extent required to provide a conforming optical elementdesign which meets said optical element design guidelines and saidapplicable set of manufacturing limitations; e) transmitting anddisplaying said conforming optical element design over theweb-interface, to said customer; f) receiving an order from saidcustomer over the web-interface for the custom freeform optical element,in the conforming optical element design; and g) manufacturing thecustom freeform optical element in fused silica to the conformingoptical element design and without the manufacture of a trial opticalelement, by the steps of: mounting a fused silica substrate on acomputer controlled XY stage; using a computer controlled focussing lenson a z stage to focus a laser beam onto the substrate a required depthto ablate the substrate; moving, via said computer of said vendor, thestages in a raster configuration to provide controlled ablation, byshot-by-shot laser writing, of the fused silica substrate; wherein saidrequired depth is determined from the file format of the conformingoptical element design which contains a grid of data whose valuesrepresent the depth of ablation of the surface of a substrate to providethe conforming optical element design.
 2. A process according to claim 1wherein step (d) includes providing a plurality of conforming opticalelement designs.
 3. A process according to claim 1 wherein the desiredoptical element design is displayed over the web-interface.
 4. A processaccording to claim 1 wherein a specification to which a conformingoptical element design will be tested and/or inspected is provided instep (a).
 5. A process according to claim 1 wherein the file format isone which involves sampling an optical surface, according to the desiredoptical element design, with a grid in order to describe the opticalelement surface to an external computer program with sufficientresolution.
 6. A process according to claim 1 wherein the manufacturingprocess is laser micro-machining.
 7. A process according to claim 1wherein the process includes a step of making payment for the opticalelements via the web-interface.
 8. A process according to claim 1wherein steps (c) and (d) are automated, by the provision of computerprograms which operate on the input desired optical element design file.9. A process according to claim 1 wherein the process includes the stepsof adding optional specifications to the desired optical element design.